AFAIK ESS doesn't support index homing itself. What you would normally do is move the servo until the home switch is triggered, slowly back off until it releases, then activate the servo drives internal homing and wait until the drive signals it's homed.
How much variety will there be in the parts?
My first thought would of been a PLC, however you may want to look at a KFlop?
A KFlop would allow you a lot more flexibility in terms of programming (think HiCON/Galil), and gives you options to run standalone (you can program into the KFlop's flash memory what you want it to do and have it run automatically when powered on), or with a custom screen to control what you want done (could be industrial touch screen with buttons so operators are limited to what can be controlled, or even physical buttons).
However, without more details about what you're wanting to do, it's hard to give advise.